During the 1974-75 grant period, we have extended our previous conformational studies of alanine oligomers ad polymers and of poly(S- beta-aminobutyric acid) to sequential copolypeptides of alanine and R- ,S-, and R,S-beta-aminobutyric acid. In hexafluoroisopropanol and hexafluoroacetone solutions, circular dichroism studies suggest that the polymer containing the S-isomer exists in a beta-conformation, which is enhanced by the addition of water, while the R- and R,S-isomers have random-coil confirmations in both pure and aqueous solvent mixtures. Polarized infrared studies indicate that all three polymers have cross- beta conformations in the solid state. We have developed a new and useful technique for determining the infrared dichroism of peptides, polypeptides and biopolymers generally by incorporation in polyoxyethylene films. This technique can give valuable conformational information in the N-H stretch (3300 cm to minus 1 power) and amide I and II (1700-1500 cm to minus 1 power) regions for peptides, polypeptides and proteins. This information had previously only been available for high molecular-weight materials which can form fibers or films. The usefulness of circular dichroism has been greatly enhanced by our development of a new technique which uses ultrathin cells (0.001 cm) and a computerized noise-averaging and plotting system. By this method we are able to measure spectra to low wavelengths (200 nm or less) at normal concentrations in solvents which would normally be opaque below 220-230 nm. We are applying both of these techniques to the study of conformations of biopolymers and their model compounds.